BACKGROUND:With the development of modern pathological techniques, the misdiagnosis rate has been reduced remarkably, but special stains are still the most important method for pathological diagnosis. OBJECTIVE:To compare the advantages and disadvantages of different special stains used for observing the structure of human lumbar facet joints. METHODS:The specimens of facet joint cartilage at L4/5 level were collected from patients undergoing lumbar surgery, and then stained with hematoxylin-eosin, safranin O, toluidine blue, Masson, and saranin-O-fast green for structure observation. RESULTS AND CONCLUSION:The structure of the articular cartilage could be observed clearly through hematoxylin-eosin, toluidine blue, and saranin-O-fast green staining. The cartilage surface, tidemark, and subchondral bone were shown by the hematoxylin-eosin staining, with the presence of violet chondrocyte nuclei. Safranin-O-fast green staining showed the four layers of the cartilage clearly, including the shallow layer (cartilage surface), middle layer (spherical cells arranged in disorder), columnar cell layer (large and multinucleated chondrocytes arranged neatly), tidemark, subchondral bone layer; and the cartilage matrix was reddish uniformly, the subchondral bone was green, and the cartilage and bone tissue showed a striking contrast. The cartilage structure was unclear in toluidine blue staining, with clear nuclei and almost no coloring cytoplasm, but the matrix appeared with slight purplish blue. Safranin O staining showed that the cartilage was red, which had no obvious boundary with the cartilage matrix, and chondrocytes were stained lightly. Masson staining showed clear collagen fibers, but the structures of the cartilage and subchondral were obscure. To conclude, safranin-O-fast green staining can achieve the best results, followed by hematoxylin-eosin staining and Masson staining in turn.

BACKGROUND:Lumbar facet arthritis is one of the main causes of low back pain.At present,MRI is mainly used for preliminary diagnosis,and there is still a certain probability of missed diagnosis and misdiagnosis.Therefore,MR T2* mapping imaging technology is expected to become an important means of quantitative detection of cartilage damage in lumbar facet arthritis. OBJECTIVE:To investigate the application value of MR T2* mapping imaging technique in quantitative analysis of cartilage damage and degeneration of lumbar facet joint. METHODS:A total of 110 outpatient or inpatient patients with low back pain in Fourth Affiliated Hospital of Nanjing Medical University from April 2020 to March 2022 were collected and set as case group.At the same time,80 asymptomatic volunteers were recruited as the control group.T2* mapping transectal images and T2WI images were obtained by 3.0T MR Scanning for the facet joints of all included subjects L1-S1.Weishaupt grading and T2* value measurement were performed for all facet joint cartilage,and the data were collected for parallel statistical analysis.The comparison of T2* values of facet joint cartilage between different articular Weishaupt grades was performed by one-way analysis of variance. RESULTS AND CONCLUSION:(1)Statistical analysis found that the T2* value of lumbar facet joint cartilage in the case group(17.6±1.5)ms was significantly lower than that in the control group(21.4±1.3)ms(P<0.05).(2)In the case group,with the hierarchical increase of lumbar facet joint Weishaupt,the T2*value of facet joint cartilage also showed a gradual decreasing trend,and the difference was statistically significant(P<0.05).(3)It is concluded that T2*mapping can better display the early pathological changes of lumbar facet joint cartilage injury,and T2* value of lumbar facet joint cartilage can quantitatively evaluate the degree of lumbar facet joint cartilage injury.T2* mapping imaging technique can provide a good theoretical basis for the imaging diagnosis of the early cartilage injury induced by lumbar facet arthritis and has important clinical application value.

Ameloblastoma is a benign tumor characterized by locally invasive phenotypes,leading to facial bone destruction and a high recurrence rate.However,the mechanisms governing tumor initiation and recurrence are poorly understood.Here,we uncovered cellular landscapes and mechanisms that underlie tumor recurrence in ameloblastoma at single-cell resolution.Our results revealed that ameloblastoma exhibits five tumor subpopulations varying with respect to immune response(IR),bone remodeling(BR),tooth development(TD),epithelial development(ED),and cell cycle(CC)signatures.Of note,we found that CC ameloblastoma cells were endowed with stemness and contributed to tumor recurrence,which was dominated by the EZH2-mediated program.Targeting EZH2 effectively eliminated CC ameloblastoma cells and inhibited tumor growth in ameloblastoma patient-derived organoids.These data described the tumor subpopulation and clarified the identity,function,and regulatory mechanism of CC ameloblastoma cells,providing a potential therapeutic target for ameloblastoma.

Objective To assess the feasibility and the value of MR T2 * mapping in valuing the early degeneration of lumbar intervertebral disc quantificationally.Methods 67 patients with low back pain and 21 healthy volunteers were chosen for the study.The two groups both underwent 3.0T MR with the axial T2 WI and T2 * mapping images in 440 discs of L1-S1.We graded all intervertebral discs by Pfirrmann score,and measured the T2 * values of annulus fibrosus(AF) and nucleus pulposus(NP).Results The T2 * values of the anterior AF and the NP among different Pfirrmann grades were statistically significant (P =0.001;P =0.000,respectively).There was significant difference in T2 * values of the anterior AF at L3/L4 between patients and volunteers (P=0.043);The T2 * values of the NP at L2/L3,L3/L4,L4/L5,L5/S1 between the two groups were significant difference (P＜0.05).There was also distinct difference in T2 * values of the posterior AF at L1/L2 and L4/L5 between the two groups (P＜0.05).Conclusion The lumbar intervertebral disc degenerates from the NP to posterior AF,and mainly occurs at L4/L5.The T2 * mapping technique can provide a good basis for diagnosing in lumbar intervertebral disc degeneration.

Tooth development is a complex process that involves precise and time-dependent orchestration of multiple genetic, molecular, and cellular interactions. Ameloblastin (AMBN, also named "amelin" or "sheathlin") is the second most abundant enamel matrix protein known to have a key role in amelogenesis. Amelogenesis imperfecta (AI [MIM: 104500]) refers to a genetically and phenotypically heterogeneous group of conditions characterized by inherited developmental enamel defects. The hereditary dentin disorders comprise a variety of autosomal-dominant genetic symptoms characterized by abnormal dentin structure affecting either the primary or both the primary and secondary teeth. The vital role of Ambn in amelogenesis has been confirmed experimentally using mouse models. Only two cases have been reported of mutations of AMBN associated with non-syndromic human AI. However, no AMBN missense mutations have been reported to be associated with both human AI and dentin disorders. We recruited one kindred with autosomal-dominant amelogenesis imperfecta (ADAI) and dentinogenesis imperfecta/dysplasia characterized by generalized severe enamel and dentin defects. Whole exome sequencing of the proband identified a novel heterozygous C-T point mutation at nucleotide position 1069 of the AMBN gene, causing a Pro to Ser mutation at the conserved amino acid position 357 of the protein. Exfoliated third molar teeth from the affected family members were found to have enamel and dentin of lower mineral density than control teeth, with thinner and easily fractured enamel, short and thick roots, and pulp obliteration. This study demonstrates, for the first time, that an AMBN missense mutation causes non-syndromic human AI and dentin disorders.
Adult ; Amelogenesis Imperfecta ; genetics ; Cells, Cultured ; China ; Codon ; Dentin ; abnormalities ; ultrastructure ; Female ; Humans ; Male ; Microsatellite Repeats ; Microscopy, Electron, Scanning ; Middle Aged ; Mutation, Missense ; Pedigree ; RNA ; analysis ; Transfection ; Whole Exome Sequencing